Calibration and Verification

Congratulations. It is very nice work, and very clearly and concisely explained so the interested public can understand. Keep up with the good work.

I do have two related questions/comments. You probably have done these things already but chose not to elaborate on them in a communication intended for the lay public who probably doesn't have the patience to follow these details. I would appreciate it if you could direct me to the proper link where these details can be found.

First, I suppose your instruments are calibrated to traceable standards and the calibration is kept up to date.

Second, I wonder if you have done any verification of your entire data collection procedure. Have you done an "experiment" in which you prepare a sample simulating rainwater with KNOWN concentration of the isotopes you are trying to measure. The concentration of these isotopes should be in the range of concentrations found in actual rainwater collected on your roof. Put this simulated sample through the same procedures of collection on the tarp, transfer to the beaker, distillation and measurement and data reduction, etc. Does the result agree with the what you put in your simulated sample? To avoid bias or systematic errors arising from your detectors, it would be better that the isotopes that you introduce into your simulated sample came from a different (trusted) laboratory, characterized by THEIR personnel using THEIR equipment.

Again, let me emphasize that you have done very nice work that is of great public interest. I just like to see that as many of the loose ends are tied up as possible.